If you already have 2008.1 RC2 (mandriva-linux-2008-spring-rc2-one-KDE-int-cdrom-i586.iso)
and you want the official released version (mandriva-linux-one-2008-spring-KDE-int-cdrom-i586.iso)
you can save time and bytes by using rsync. Open a command console in the directory of your RC2 iso file and rename it to the same name as the 2008.1 Final, or make a copy. I made a hard linked copy like this:
CODE
ln mandriva-linux-2008-spring-rc2-one-KDE-int-cdrom-i586.iso mandriva-linux-one-2008-spring-KDE-int-cdrom-i586.iso

Issue the following command:
CODE
rsync -aP distrib-coffee.ipsl.jussieu.fr::pub/linux/MandrivaLinux/official/iso/2008.1/mandriva-linux-one-2008-spring-KDE-int-cdrom-i586.iso ./

You will then see:
CODE
receiving file list ...
1 file to consider
mandriva-linux-one-2008-spring-KDE-int-cdrom-i586.iso
   730503168 100%  147.75kB/s    1:20:28 (xfer#1, to-check=0/1)

sent 189082 bytes  received 271055291 bytes  48285.60 bytes/sec
total size is 730503168  speedup is 2.69

As you can see, I only downloaded 271055291 bytes, that's 37.1% of the file, and yet I got the whole 2008.1 iso file which is a 730503168 byte file.

This method may also work with other ISOs that have much in common.